Lesion Patterns and Etiology of Ischemia in Superior Cerebellar Artery Territory Infarcts

Abstract

Background and Purpose: Infarcts in the territory of superior cerebellar artery (SCA) are uncommon. The clinical, and etiological mechanisms of different infarct patterns of SCA are not well known. Diffusion-weighted imaging (DWI) is superior to conventional magnetic resonance imaging for detecting acute small and multiple ischemic lesions. Methods: We studied 60 patients with lesions involving SCA territory proved by DWI, which have been selected from 3,800 patients with first ischemic stroke consecutively admitted to our stroke unit over a period of 5 years. Results: There are 7 distinctive SCA lesion patterns: (1) a lesion was found in the medial (m) branch territory of SCA (mSCA) in 14 patients; (2) a lesion in the lateral (l) branch territory of SCA (lSCA) was seen in 9 patients; (3) a coexisting lesion involving mSCA and lSCA was found in 9 patients; (4) a lesion in cortical borderzones between SCA and m/l branches of the posterior inferior cerebellar artery (PICA) was observed in 6 patients; (5) a lesion in deep borderzones between lSCA and mSCA, and lPICA and mPICA was present in 8 patients; (6) a lesion involving the medial rostral cerebellum between the right and left SCA was found in 4 patients; (7) multiple lesions involving SCA and other vertebrobasilar artery territories were present in 10 patients. The main cause was possible artery-to-artery embolism from atherosclerotic vertebrobasilar arteries to distal branches of SCA in 20 patients (33%). Fourteen patients had a source of cardioembolism (23%), and 6 patients (8%) had concomitant atherosclerotic vertebrobasilar artery disease and a source of cardioembolism. Conclusions: An acute ischemic lesion in the SCA territory is mainly multiple. The lSCA territory was the most involved area. Small territorial infarcts were frequently associated with large territorial SCA infarcts. Borderzone SCA infarcts occurred in one third of the patients with transient benign symptoms. Mass effects are unusual despite the large amount of SCA involvement. Our results supported the fact that embolism is the predominant stroke mechanism in the SCA territory infarction.

Association between Small Deep Cerebellar Ischemic Lesion and Small-Vessel Disease

“…It is well known that embolism from an arterial or cardiac source is the most common cause of territorial cerebellar infarcts [1,2,3,4,5,6,7]. Previous studies showed that small nonterritorial cerebellar infarcts usually have the same embolic mechanism as territorial infarcts, and they sometimes have a hemodynamic mechanism [8,9,10,11].…”

Frequency and Clinical Significance of Acute Bilateral Cerebellar Infarcts

“…There have been some reports of BCI, but they have limitations [2,3,4,5,6,7,8,9]. Firstly, they did not compare clinical features or radiological characteristics between UCI and BCI because the total number of patients was so small (3–12 cases) [4, 7].…”

“…Thirdly, they have not delineated the overall features or mechanisms of BCI because they focused on only 1 territory amongst the cerebellar arteries. Finally, some studies on acute cerebellar infarcts contained no mention of the BCI [6, 8, 9]. A review of studies on BCI can be found in table 1.…”

Radiographic Features of Cerebellar Disease: Imaging Approach to Differential Diagnosis

“…Typically artery-to-artery embolism (33-60%) or cardioembolism (20-23%) (Terao et al 2005;Kumral et al 2005;Chaves et al 1994) Hemorrhagic infarcts in 13% of cases (Terao et al 2005) Most commonly involving the PICA (60%) and SCA (40%) territories (Terao et al 2005;Min et al 1999;Marinkovic et al 1995) Venous infarcts (Fig. 27.32) Secondary to venous thrombosis in the posterior fossa, predominantly the straight and sigmoid sinuses (Ruiz-Sandoval et al…”